U.S. Reactors Ride Out The Storm

From the Energy Collective: U.S. Reactors Ride Out The Storm

The nuclear reactors in eleven eastern states were mostly unaffected by the passage of Hurricane Irene over the weekend of August 26-28, 2011. Two reactors shut down safely and several others reduced power.

At Constellation’s Calvert Cliffs site in Maryland one reactor was taken off line when a piece of aluminum siding was ripped off a building by 90 mph gusts hitting a transformer in the switchyard. The transformer shut down tripping the turbine which caused the reactor to go offline. The other reactor remained online at 100% power throughout the storm.

In New Jersey Exelon’s Oyster Creek plant took preventative action shutting down at 5 PM Saturday August 27th. Plant staff walking down the plant on Sunday August 28th found no damage to the facility.

In North Carolina Progress reduced power at its Brunswick site, but kept the reactors running. In a similar move, Dominion reduced power at its Millstone site on the shore of Long Island Sound in Connecticut. There was no reported damage at either plant.

Entergy reported that there was no disruption of any of its reactors in four states. Indian Point in NY, Vermont Yankee in VT, Pilgrim in Massachusetts, and Seabrook in NH all operated at 100% power through the storm.

Similarly, PSEG’s Hope Creek and Salem reactors in southwestern New Jersey operated at 100% despite having the storm pass over them.

The NRC reported that none of the plants in areas hit by the storm on Saturday lost offsite power from the grid. However, several plants reported some of their emergency sirens were knocked offline by power outages. All plants have back-up options for such a situation.

How did they do it?

Nuclear energy facilities are prepared to safely withstand high winds and heavy rain as the eastern United States braces for Hurricane Irene to make landfall this weekend.

When hurricanes occur, electric utilities operating nuclear energy facilities take specific actions mandated by U.S. Nuclear Regulatory Commission guidelines and the plants’ emergency preparedness plan. These include:

* Plant personnel monitor storm conditions, paying close attention to the path of a storm and wind speeds at the site.
* Personnel inspect the entire facility and secure or move any equipment that could possibly become airborne due to high winds.
* Each plant site has numerous emergency backup diesel generators that are tested and ready to provide electricity for critical operations in the event of a loss of off-site electricity supply.
* Diesel fuel tanks are checked and topped off to ensure there is a minimum of seven days of fuel to power backup generators.
* As a precaution, a reactor will be shut down at least two hours before the onset of hurricane-force winds at the site, typically between 70 and 75 miles per hour.
* Twelve hours before Hurricane Irene approaches nuclear energy facilities on the East Coast, plant operates at each site will provide status updates to the Nuclear Regulatory Commission.

If there is a loss of off-site power, reactors automatically shut down as a precaution and the emergency backup diesel generators begin operating to provide electrical power to plant safety systems. Plant operators also may manually shut down the reactor as a precaution even if off-site power is still available.

Nuclear power plants are the most robust facilities in the U.S. infrastructure, with reactor containment structures composed of steel-reinforced concrete that have proven their ability to withstand extreme natural events.

In addition, nuclear plant operators are trained and tested one out of every six weeks to safely manage extreme events such as hurricanes. Plant operators also have multi-day staffing plans, and resources, to ensure that personnel are on-site and prepared to respond to situations that may arise as a result of the storm.

The transmission and distribution infrastructure of the region didn’t fare so well under the impact of 90 mph winds. Up and down the east coast nearly three million people are without power and more outages are expected as the hurricane heads late Sunday north northeast at 25 mph into New England states. Late Sunday most of the east coast began a soggy process of cleaning up after the storm.